Receiving device for bond-detectors.



PATENTEDDBG. 4, 1906.

I H. A. WATSON. RECEIVING DEVICE FOR BOND DETECTORS.

APPLICATION FILED APR-13.1905.

//VVE W/ TNEESES: GIL 9.7 W6.

THE NORRIS PETERS ca. WASHINGTON. D. c.

HARRIS A. lVATSON, OF SYLVANIA, OHIO.

RECEIVING DEVICE FOR BOND-DETECTORS- Specification of Letters Patent.

Patented Dec. 4:, 1906.

Application filed April 13, 1905. Serial No. 255,363.

To aZZ whom it may concern.-

Be it known that I, HARRIS A. WATSON, a citizen of the United States,and a resident of Sylvania, in the county of Lucas and State of Ohio,have invented certain new and useful Improvements in Receiving Devicesfor Bond-Detectors and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being'had to the accompanying drawings, and to thefigures of reference marked thereon, which form a part of thisspecification.

My invention relates to instruments for detecting and examining thecondition of the connecting-bonds of rails on electric railroads and thelike, and has for its object the provision of a device of this classthat is extremely sensitive in its nature and adapted to convey to theoperator sounds varying in strength as the bond is more or lessdefective.

The invention is fully described in the fol lowing specification andshown in the accompanying drawings, in which Figure 1 is a centrallongitudinal section of the instrument embodying my invention, taken onthe dotted line y 3 in Fig. 2. Fig. 2 is a cross-section of the same,taken on the dotted line m in Fig. 1; and Fig. 3 is a side elevation oftwo bonded rails with the con tact piece or foot to which the detectoris connected bridging the joint of the rails and shown in longitudinalsection.

Referring to the drawings, 1 represents a cylindrical casing of anysuitable insulating material, the outer end of which casing is closed,as shown at 2. Mounted centrally within the casing 1 is a soft-iron core3, which has its inner end secured to the disk 2 and its outer endpassed through an aperture provided centrally in the larger disk 4,which disks are made of insulating material and form the ends of a spoolof which the core acts as-the shank. Around the core 3 are the twowindings 5 and 6, forming the primary and secondary coils, respectively,of an induction-coil, the two windings being separated from each otherby an insulating-strip 7 and the coil 6 being of finer wire than thecoil 5. The primary coil 5 has its two terminals or poles passed throughthe end of the casing and connected with the line-wires 8 through thebinding-posts 9, which latter are secured to the casing end. Theterminals of the secondary coil 6 pass from the opposite end of thespool through the disk 4c and connect with the separate binding-screws10 in said disk.

Mounted on the outer face of the disk 4 is a cylindrical shell 11,diametrically of which and directly over the exposed end of the core 3is secured the permanent magnet 12, the poles 12 of which are broughtclose together in the center of the shell and bent outwardly in parallelrelation. A fine coil of wire 13 is wound upon a spool 13 on each pole12- and have two of their terminals connected with the two terminals ofthe secondary coil 6 through the binding-screws 10, as shown in Fig. 2,thus closing the circuit between the secondary coil 6 and coils 13. Athin diaphragm 14, of suitable material to be attracted by the poles ofthe magnet 12, is placed over the open end of the shell 11 in closeposition to the ends of the poles 12 and secured in place by acentrally-apertured cap or cover 15, which is threaded to the rim ofsaid shell.

The line-Wires 8 have connection with a hollow joint-bridging member 16,which is provided at its ends with the insulated contact-pieces 16 forcontact with the two rails 17. A hollow upright 18 may be secured to theupper portion of the bridging member for elevating the line-wires 8 tothe desired height. The line-wires 8 connect with the binding-posts 19at the upper end of the upright and communicate with the contactpieces16 or poles of the member 10 through the wires 20, which pass downthrough the upright 18 and bridge member 16.

The operation of my invention is as follows: In detecting the conditionof a bond the joint of two connecting-rails is bridged over by themember 16, the contact-pieces 16 being placed in contact therewith.Should the bond-wire be even slightly defective, a portion of thecurrent passing along the rails would be taken up by the contact-pieces16 and caused to pass through the detecting instrument. The passing ofthe current through the primary coil 5 converts the core 3 into anielectromagnet, which acts directly upon the permanent magnet 12 andinduces a current in the secondary coil 6, which current is communicatedto the fine coils 13, and thereby greatly strengthens the magneticeffect of the poles of the magnet 12. Should the bond be only slightlydefective, the electromagnet is not sufliciently energized tosusceptibly affect the strength of the magnet 12, said magnet beingprincipally strengthened by the induced current passing through thecoils '6 and 13, which causes a vibration or undulation of the diaphragmand a consequent sound to be emitted from the instrument. Should thebond be quite badly defective, the permanent magnet is acted on both bythe electromagnet and the induced current, thereby causing a much loudersound to be emitted from the instrument, the sound increasing ordiminishing in strength as the bond is more or less defectwe.

I am aware that an ordinary telephone-receiver may be used for detectinga defective bond but I have found by experimenting that by the use ofsuch instrument a slight defect cannot be detected, nor can the operatortell by its use to what degree the bond is defective. By constructingthe instrument in the manner described and shown the operator can notonly detect a very slight defect in the bond, but can also tell by thenature of the sound emitted by the vibrations of the diaphragm to whatextent the bond is defective.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In combination, a shell, a diaphragm mounted therein, a polarizedmagnet also mounted in the shell with the diaphragm on one side thereofand an induction-coil located on the opposite side of said magnet fromthe diaphragm, in axial alinement with the shell and to the exteriorthereof, circuit connection between the secondary coil of saidinduction-coil and the coil of the polarized magnet, and circuitconnection between the primary coil and the line-wires.

, 2. In combination, a shell, a diaphragm mounted therein, a polarizedmagnet housed within the shell and an induction-coil located on the sameside of the diaphragm as said i magnet and without the shell with itscore so disposed as to influence the polarized magnet, circuitconnection from the secondary winding of the induction-coil to thewinding of the polarized magnet, and circuit connections between theprimary windings of the inductioncoil and the line-wires.

3. In combination, a diaphragm, an induction-coil disposed axially inrelation thereto having a soft-iron core with its end, adjacent thediaphragm, exposed, a magnet located between said end and the diaphragmand designed to be influenced by said core, a helix-winding about thesaid magnet, circuit connections'between the same and the secondarywindingsof the induction-coil and circuit. connections between theprimary windings and the line-wires.

4. A receiver comprising a diaphragm, an induction-coil and magnetsinterposed between one end of the core of said coil and the diaphragm,exposed to said end and having poles closely adjacent and extending in adirection axially of the core helix-windings about said magnets incircuit with each other, circuit connection between said windings andthe secondary windings of the induction-coil and circuit connectionbetween the primary windings of the induction-coil and the linewires.

5. A receiver comprising an induction-coil having a core projecting atone end through the windings thereof, an insulated block providing oneend for the coil and having an axial opening to receive the end of thecore and through which the same is exposed, a shell mounted on theblock, a diaphragm mounted in the shell, magnets including two platesextending diametrically of the shell directly over the exposed end ofthe core and having their adjacent ends in alinement with the coredeflected to extend in a direction parallel with the axis of said coreand diaphram field-windings on said deflected ends, circuit connectionbetween said windings and the secondary winding of the induction-coil,and circuit connection between the primary windings of theinduction-coil and the line-wires.

In witness whereof I have hereunto signed my name to this specificationin the presence of two subscribing witnesses.

HARRIS A. WATSON.

